The unrelenting movement of Americans into western North America and the concept of a Manifest Destiny are responsible for the Mexican- American War including other causes. The annexation of Texas and other western areas had an impact on American’s foreign relations due to economics. The chaos with the southern states to gain more slave states increased their political power. Those in the free states to the north tended to hold this view of the war. Texas gained Americans as they ignored the slavery restrictions.

People in the North feared Texas would join the union as a slave state since there were slaves in Texas. Southern states wanted Texas so their military volunteers went to fight against Mexico to hopefully gain Texas as a slave state. By official record the Mexican War lasted from 1846 to 1848, but the origins of hostility may have dated to 1836 due to a history. The war for the territory that the United States intended to possess was welcomed by the United States eager for the nation to grow with territorial rights